TY - JOUR
T1 - Transport characteristics of Chinese haze over Northern Taiwan in winter, 2005-2014
AU - Wang, Sheng Hsiang
AU - Hung, Wei Ting
AU - Chang, Shuenn Chin
AU - Yen, Ming Cheng
N1 - Publisher Copyright:
© 2015 Elsevier Ltd.
PY - 2016/2/1
Y1 - 2016/2/1
N2 - Haze over east China has been extensively studied, but its impacts on downwind areas remain unclear. In this study, we applied long-term (9 yr) air quality, meteorological, and ground-based remote sensing data for investigating the transported haze events over Northern Taiwan in winter. Thirty-six haze events were identified using a statistical method and information pertaining to wind direction and episode duration. In contrast to haze events over China, the transported haze exhibits low relative humidity (approximately 70%) and high wind speed (approximately 5 m s-1) and is associated with a migrating high-pressure system. The mass concentration of fine particulate matter (PM2.5) for the haze events was 57.1 ± 13.6 μg m-3, nearly four times higher than that of the background (13.7 ± 7.4 μg m-3). Such high PM levels persisted for 120 h in winter. Back trajectory analysis suggests that the haze particles were transported from the east coast of China, particularly from the Yangtze River Delta (YRD) area with a traveling time of nearly 28 h. Lidar observations clarify that the Chinese haze was transported to Northern Taiwan and accompanied by low clouds and a temperature inversion layer, which confined the particles to a height of less than 1 km. Moreover, a relatively high PM2.5 concentration (65.0 μg m-3) was observed when air mass stagnated over YRD before advancing to Taiwan. This scenario, most frequently seen in the winter of 2013, resulted in the highest historical PM2.5 concentration (approximately 77.2 μg m-3). We propose that the heavy haze year is primarily attributable to synoptic weather variability and less to climate.
AB - Haze over east China has been extensively studied, but its impacts on downwind areas remain unclear. In this study, we applied long-term (9 yr) air quality, meteorological, and ground-based remote sensing data for investigating the transported haze events over Northern Taiwan in winter. Thirty-six haze events were identified using a statistical method and information pertaining to wind direction and episode duration. In contrast to haze events over China, the transported haze exhibits low relative humidity (approximately 70%) and high wind speed (approximately 5 m s-1) and is associated with a migrating high-pressure system. The mass concentration of fine particulate matter (PM2.5) for the haze events was 57.1 ± 13.6 μg m-3, nearly four times higher than that of the background (13.7 ± 7.4 μg m-3). Such high PM levels persisted for 120 h in winter. Back trajectory analysis suggests that the haze particles were transported from the east coast of China, particularly from the Yangtze River Delta (YRD) area with a traveling time of nearly 28 h. Lidar observations clarify that the Chinese haze was transported to Northern Taiwan and accompanied by low clouds and a temperature inversion layer, which confined the particles to a height of less than 1 km. Moreover, a relatively high PM2.5 concentration (65.0 μg m-3) was observed when air mass stagnated over YRD before advancing to Taiwan. This scenario, most frequently seen in the winter of 2013, resulted in the highest historical PM2.5 concentration (approximately 77.2 μg m-3). We propose that the heavy haze year is primarily attributable to synoptic weather variability and less to climate.
KW - Aerosol vertical distribution
KW - Chinese haze
KW - Long-range transport
KW - PM
UR - http://www.scopus.com/inward/record.url?scp=84949229451&partnerID=8YFLogxK
U2 - 10.1016/j.atmosenv.2015.11.043
DO - 10.1016/j.atmosenv.2015.11.043
M3 - 期刊論文
AN - SCOPUS:84949229451
SN - 1352-2310
VL - 126
SP - 76
EP - 86
JO - Atmospheric Environment
JF - Atmospheric Environment
ER -